Grassy Key – Middle Florida Keys

Grassy KeyGrassy Key, Florida, is an island in the middle Florida Keys. It is located at MM 57—60, between the Duck Key to the NE and Crawl Key to the SW.

It is one of the northernmost islands in a chain of islands that comprises the City of Marathon, Florida incorporated in 1999.

The Dolphin Research Center is located on Grassy Key at mile marker 59.